"The performance of a series of mineral oil based quenchants has been investigated using the CHTE Quench Probe System and probe tips of 4140 steel to determine the cooling rate, heat transfer coefficient, Hardening Power (HP) and Tamura’s V indices in terms of the physical properties of quenchants; e.g. viscosity and oil start temperature. The Quench Factor, Q, was also calculated in terms of the hardness of the quenched parts. The lumped parameter approximation was used to calculate the heat transfer coefficient as a function of temperature during quenching. The results revealed that the maximum cooling rate increases with decrease in quenchant viscosity. As viscosity increases, Tamura’s V is nearly constant, while the HP decreases. For the selected oils, cooling ability of quenching oil increases with the increase in oil operating temperature, reaches a maximum and then decreases. The heat transfer coefficient increases with the increase in hardening power and maximum cooling rate. As the viscosity increases, the quench factor increases, which indicates the cooling ability of the oil decreases since the higher quench factor means the lower cooling ability of the oil. The hardness decreases with the increase in quench factor. Also the effect of surface oxides during quenching in commercial oils is studied. It was found that for 4140 steel probes the formation of oxide in air increases the cooling rate and heat transfer coefficient, the cooling rate curve of 4140 steel probe heated in argon shows clear Leidenfrost temperature, the oxide layer may require a significant thickness to cause the decrease in heat transfer coefficient. For 304 stainless steel probes the cooling rate and heat transfer coefficient are quite similar in air and in argon."

Made available in DSpace on 2014-06-11T19:30:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-07Bitstream added on 2014-06-13T21:01:23Z : No. of bitstreams: 1 000750418.pdf: 8347882 bytes, checksum: f38265d2f19eb62c9053d91c1e58a41b (MD5) / Neste trabalho verificamos o potencial das técnicas de absorção UV-Vis e de fluorescência para o monitoramento da degradação do óleo mineral isolante (OMI), utilizado em transformadores em função do seu aquecimento. Foram realizadas medições e análise de mapas de contorno (excitação – emissão) de amostras de óleo mineral isolante novo e regenerado não diluídas e diluídas em hexano após aquecimento sistemático das mesmas e retorno à temperatura ambiente. Também foram obtidos espectros de absorção das amostras diluídas. As medições citadas foram realizadas para monitorar a degradação de amostras não diluídas de óleos minerais isolantes novos e regenerados, de forma a verificar a aplicabilidade das técnicas sem um preparo inicial das amostras. Os resultados mostraram que os valores de absorção e fluorescência sofrem mudanças sistemáticas a partir de cerca de 150°C, temperatura na qual a degradação do óleo se torna mais pronunciada. Foram observados comportamentos similares de absorção e fluorescência, tanto para o óleo novo quanto para o regenerado, o que indica que esta técnica óptica simples pode ser usada para o monitoramento contínuo da qualidade do óleo, independentemente da sua fonte. Os possíveis mecanismos responsáveis pelas alterações também são discutidos, tal como o efeito da geometria da configuração experimental das medições de fluorescência. Os resultados fornecem informações para o desenvolvimento de dispositivos portáteis, simples e de custo potencialmente baixo, capazes de verificar a qualidade do óleo mineral isolante em laboratórios e ambientes remotos sem a necessidade de qualquer preparação prévia da amostra. / In this study we verify the potential of the UV-Vis absorption and fluorescence techniques to monitor the degradation of the insulating mineral oil (IMO) used in transformers depending on their heating. Measurement and analysis of contour maps (excitation - emission) were taken from samples of new and regenerated insulating mineral oils diluted and undiluted in hexane after systematically heating and bringing them back to room temperature. Absorption spectra were also obtained from diluted samples. The mentioned measurements were performed to monitor the degradation of new and regenerated insulating mineral oil undiluted samples in order to verify the applicability of the techniques without prior sample preparation. The results showed that the values of absorption and fluorescence underwent systematic changes starting at about 150 °C, temperature at which oil degradation becomes more pronounced. Similar absorption and fluorescence behaviors for both new and regenerated oils were observed, indicating that this simple optical approach may be used for continuous monitoring of oil quality, regardless of its source. The possible mechanisms responsible for the changes are also discussed, and the effect of the geometry of the experimental setup of the fluorescence measurements was investigated as well. The results provide the basis for the development of portable, simple and potentially inexpensive devices, able to check the insulating mineral oil quality in laboratories and remote environments without the need of any prior preparation of the sample.

Orientador: Aparecido Augusto de Carvalho / Banca: Claudio Kitano / Banca: Darcy Hiroe Fujii Kanda / Banca: Anderson Rodrigues Lima Caires / Banca: Samuel Leite de Oliveira / Resumo: Neste trabalho verificamos o potencial das técnicas de absorção UV-Vis e de fluorescência para o monitoramento da degradação do óleo mineral isolante (OMI), utilizado em transformadores em função do seu aquecimento. Foram realizadas medições e análise de mapas de contorno (excitação - emissão) de amostras de óleo mineral isolante novo e regenerado não diluídas e diluídas em hexano após aquecimento sistemático das mesmas e retorno à temperatura ambiente. Também foram obtidos espectros de absorção das amostras diluídas. As medições citadas foram realizadas para monitorar a degradação de amostras não diluídas de óleos minerais isolantes novos e regenerados, de forma a verificar a aplicabilidade das técnicas sem um preparo inicial das amostras. Os resultados mostraram que os valores de absorção e fluorescência sofrem mudanças sistemáticas a partir de cerca de 150°C, temperatura na qual a degradação do óleo se torna mais pronunciada. Foram observados comportamentos similares de absorção e fluorescência, tanto para o óleo novo quanto para o regenerado, o que indica que esta técnica óptica simples pode ser usada para o monitoramento contínuo da qualidade do óleo, independentemente da sua fonte. Os possíveis mecanismos responsáveis pelas alterações também são discutidos, tal como o efeito da geometria da configuração experimental das medições de fluorescência. Os resultados fornecem informações para o desenvolvimento de dispositivos portáteis, simples e de custo potencialmente baixo, capazes de verificar a qualidade do óleo mineral isolante em laboratórios e ambientes remotos sem a necessidade de qualquer preparação prévia da amostra. / Abstract: In this study we verify the potential of the UV-Vis absorption and fluorescence techniques to monitor the degradation of the insulating mineral oil (IMO) used in transformers depending on their heating. Measurement and analysis of contour maps (excitation - emission) were taken from samples of new and regenerated insulating mineral oils diluted and undiluted in hexane after systematically heating and bringing them back to room temperature. Absorption spectra were also obtained from diluted samples. The mentioned measurements were performed to monitor the degradation of new and regenerated insulating mineral oil undiluted samples in order to verify the applicability of the techniques without prior sample preparation. The results showed that the values of absorption and fluorescence underwent systematic changes starting at about 150 °C, temperature at which oil degradation becomes more pronounced. Similar absorption and fluorescence behaviors for both new and regenerated oils were observed, indicating that this simple optical approach may be used for continuous monitoring of oil quality, regardless of its source. The possible mechanisms responsible for the changes are also discussed, and the effect of the geometry of the experimental setup of the fluorescence measurements was investigated as well. The results provide the basis for the development of portable, simple and potentially inexpensive devices, able to check the insulating mineral oil quality in laboratories and remote environments without the need of any prior preparation of the sample. / Doutor

This thesis summarizes the findings of the current application of mineral oil taxation policy in the European Union and individual Member States. Attitude and editing this field from the perspective of the European Union is engaged in a chapter called harmonization of taxes on mineral oils in the EU. Comparative analysis of tax revenues from mineral oils in the EU is the second chapter in which I deal with the taxation of mineral oils in the Member States and their tax revenues from energy taxes, which include revenues from mineral oil. Next chapter competition duties on mineral oils focuses on the development of tax rates on mineral oils, the mobility of the tax base and the related variability in rates over time and between countries. The content of the last chapter named Evolution taxation of mineral oils from the perspective of the European Union, the EU primarily intended changes in the taxation of energy products.

Thesis (Ph.D. (Horticulture)) -- University of Western Sydney, 2002. / "A thesis submitted to the University of Western Sydney for the fulfillment of study for a degree of Doctor of Philosophy in Horticulture" "Principal supervisor: Robert Spooner-Hart, co-supervisor: Andrew Beattie, co-supervisor: Alfie Meats" Bibliography : leaves 231-265.

This thesis deals with alternative thermal degradation of electrical insulating liquids. The theoretical part describes the current state of the problem, electrical insulating liquids, their classification and types. There are described properties of electrical insulating liquids, their models of aging and diagnostic methods in accordance with the appropriate standards. In the practical part are chosen by representatives of alternative electrical insulating liquids and there are determined their dielectric characteristics in the initial state. According to the measured values is chosen five candidates for which it is designed and implemented an accelerated degradation test. During the test are measured dielectric parameters of the selected oils. Measured dependencies are mathematically approximated. In conclusion, the results are compared and physically interpreted in view of oxidation stability.

This master thesis deals with clasification of electrical insulating liquids and analysis their reological properties. Theoretical part describes viscosity and possibilities of its measurement, electrical and non-electricl properties of electrical insulating liquids and themselves electrical insulating liquids. Practical part describes measurement of viscosity and density of chosen vegetable oils, their components and transformer oils in wide temperature range. At the conclusion of the thesis, analysis of measurement results is done.

A compressible Euler-Euler computational fluid dynamics (CFD) model for vapor, gas, and pseudo-cavitation in oil-hydraulic flows is presented. For vapor, the Zwart-Gerber-Belamri (ZGB) model is used and for gas cavitation, the Lifante model. The aim is to determine the empirical parameters within the cavitation models for hydraulic oil by comparing CFD results to experiments in a realistic valve. The cavitating flow is visualized and measured for numerous operating points. By degassing, states of pure vapor cavitation are generated. The major findings are: (1) large eddy simulation turbulence modeling is essential, (2) vapor cavitation in mineral oil can be simulated very well with the ZGB model using the determined parameter, and (3) gas cavitation model provides useful results although not all details can be reflected and its scope is limited.

Subject matter of my diploma paper is {\clqq} Tax burden of road transfer in select entrepreneurial subject``. My aim is optimise tax charge of road transfer in this entrepreneurial subject. I define long-term corporeal property, manners of its acquisition and its depreciation in introductory part. Further, I describe taxes and compulsory charges, which closely bear with road transfer. I focus on tax charge in factual company, which carries bussiness in road transfer in the end. I investigate tax stress at tax and duties, which directly bear with road transfer. It is about road tax, consumer tax of mineral oils, value added tax (VAT), the duties from usages of motorways and high-roads and finally insurance of responsibility for damage caused operation of motor vehicle. I compare tax burden of two particular trucking systems the company has available and I propose options available to a possible reduction of tax charge in these two freighters.